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CIRCUUAT1NG 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  316 


AN  EXPERIMENT  IN  THE  FREE-CHOICE 
FEEDING  OF  MINERAL  SUPPLE- 
MENTS TO  DAIRY  CATTLE 


BY  W.  B.  NBVENS 


URBANA,  ILLINOIS,  DECEMBER,  1928 


AN  EXPERIMENT  IN  THE  FREE-CHOICE  FEEDING 

OF  MINERAL  SUPPLEMENTS  TO 

DAIRY  CATTLE 

By  W.  B.  XEVENS,  Assistant  Chief  in  Dairy  Cattle  Feeding 

Widespread  interest  in  the  needs  of  dairy  cattle  for  minerals  has 
been  aroused  thru  investigations  which  have  shown  that  the  produc- 
tion of  large  amounts  of  milk  by  dairy  cows  may  cause  the  loss  of 
mineral  elements  from  their  bodies. 

Investigations  have  followed  two  general  plans.  Under  one  plan, 
the  intake  and  outgo  of  minerals  have  been  measured  during  periods 
varying  from  a  few  days  to  several  weeks.  Under  the  other  plan, 
rations  high  and  low  in  minerals,  or  supplemented  by  various  mineral 
compounds,  have  been  fed  thru  one  or  more  lactation  periods,  and  ob- 
servations made  upon  the  effect  which  the  feeding  of  minerals  might 
have  on  milk  yield,  reproduction,  and  the  general  health  of  the  ani- 
mals. 

It  is  a  matter  of  common  knowledge  that  cattle  require  sodium 
and  chlorin,  the  elements  of  common  salt,  in  amounts  greater  than 
those  supplied  in  farm  feeds.  The  experiments  mentioned  above  have 
shown  that,  aside  from  sodium  and  chlorin,  the  mineral  element  most 
likely  to  be  deficient  in  rations  for  milk  production  is  calcium,  and 
that  sometimes  phosphorus  may  also  be  lacking.  It  has  been  shown 
further  that  minerals  play  a  most  important  part  in  the  nutrition  of 
dairy  cows,  and  that  mineral  deficiencies  may  result  in  profound 
effects  upon  reproductive  ability  and  health.  The  extent  of  the  losses 
which  occur,  however,  and  the  ways  in  which  they  can  with  certainty 
be  prevented,  are  still  questions  for  study,  the  investigations  not  hav- 
ing yielded  entirely  uniform  results  on  these  points. 

In  view  of  the  evident  need  for  further  information  regarding  the 
mineral  requirements  of  dairy  cows  and  the  value  of  mineral  supple- 
ments in  their  rations,  the  experiment  described  herein  was  carried  out. 
Mineral  supplements  were  provided  "free-choice"  in  feed  boxes  to 
which  the  cattle  had  access  while  in  the  exercising  yards.  The  object 
of  this  experiment  was  to  determine  whether  cattle  kept  under  ordi- 
nary herd  conditions  in  barn  and  dry  lot  would  voluntarily  supple- 
ment their  rations  with  minerals  if  given  an  opportunity.  These  trials 
extended  over  parts  of  four  years. 

Outline  of  Experiment 

The  cows  used  in  this  test  were  of  moderate  to  good  productivity, 
quite  a  number  of  them  producing  from  40  to  60  pounds  of  milk  daily 
during  the  early  part  of  the  lactation  period.  They  were  milked  but 
twice  daily.  The  animals  designated  as  the  "heifer  group"  consisted 

118 


1928]  MINERAL  SUPPLEMENTS  FOR  DAIRY  CATTLE  119 

of  the  young  daughters  of  cows  included  in  the  cow  group.  The 
heifers  ranged  in  age  from  about  six  to  twenty-four  months  of  age. 
As  they  came  into  milk,  they  were  transferred  to  the  cow  group. 

All  the  cattle  were  confined  during  the  entire  period  covered  by 
the  experiments  to  barns  and  dry  lots. 

The  ration  fed  consisted  of  corn  silage,  legume  hay,  and  a  grain 
mixture.  The  hay  was  a  good  grade  of  either  alfalfa,  soybeans,  or 
red  clover.  The  grain  mixture  consisted  of  ground  shelled  corn,  ground 
oats,  wheat  bran,  and  a  second  protein  supplement.  Corn  gluten  feed 
supplied  this  second  protein  supplement  from  August,  1924,  to  August, 
1925;  from  August,  1925,  to  August,  1927,  soybean  oil  meal  was  used; 
and  subsequent  to  August,  1927,  linseed  oil  meal  wras  used.  The  grain 
was  weighed  at  each  feeding  and  fed  to  the  milk  cowrs  in  proportion 
to  their  milk  production  and  to  the  heifers  at  a  rate  to  induce  rapid 
growth. 

The  minerals  fed  these  cattle  were  placed  in  boxes  in  their  exer- 
cising yards.  A  box  with  three  compartments  was  kept  in  the  yard 
for  the  milk  cows  and  another  in  the  yard  for  the  young  stock  (heif- 
ers) .  The  boxes  were  protected  somewhat  from  the  weather  by  means 
of  a  shed  roof  and  partially  inclosed  sides. 

Beginning  in  the  summer  of  1924  a  supply  of  very  finely  ground 
limestone1  was  kept  in  one  of  the  compartments  of  each  feed-box  and 
common  salt  in  another.  At  the  end  of  each  week  during  the  experi- 
ment the  amount  in  each  compartment  was  weighed,  and  if  still  in 
good  condition  for  feeding,  was  returned  to  the  compartment.  More 
was  added  during  the  week  as  needed  to  insure  a  continuous  supply. 

About  August  1,  1926,  after  two  years  of  limestone  supplement, 
bone  meal  was  added  in  the  third  compartment  of  each  feed-box.  This 
bone  meal  was  called  "pure  raw  bone  feeding  meal."  The  manufac- 
turer stated  that  this  product  was  made  from  selected  fresh  bones  and 
was  made  safe  for  feeding  by  treatment  with  steam  at  a  high  tempera- 
ture. It  was  nearly  free  from  odor. 

From  August  2,  1926,  to  the  end  of  the  experiment  in  November, 
1927,  the  limestone  and  the  bone  meal  were  mixed  with  common  barrel 
salt  at  the  rate  of  4  parts  of  limestone  or  bone  meal  to  1  part  of  salt. 

The  feeding  of  the  above  supplements  was  discontinued  each 
year  with  the  arrival  of  inclement  weather,  when  the  cattle  were  not 
turned  out  into  the  yards,  or  when  the  supplements  became  damp  and 
frozen  so  that  the  cattle  could  not  eat  them.  With  the  arrival  of  warm 
weather,  the  yard  feeding  was  resumed.  During  the  times  when  no 
mineral  supplements  were  fed  in  the  yard,  bone  meal  and  salt  were 
incorporated  in  the  grain  mixture  to  the  extent  of  1.5  per  cent  each. 

lrThis  product  was  furnished  for  the  experiment  thru  the  courtesy  of  the 
Michigan  Limestone  and  Chemical  Company,  of  Buffalo,  New  York.  The  com- 
pany stated  that  85  percent  of  the  limestone  would  pass  thru  a  200-mesh  sieve. 


120  BULLETIN  No.  316  [December, 

Salt  was  supplied  in  the  grain  mixture  at  the  rate  of  1  percent  during 
the  yard  feeding  of  mineral  supplements. 

It  was  impossible  to  avoid  small  errors  in  this  type  of  feeding. 
At  times  rain  would  blow  into  the  feed  boxes,  or  during  damp  weather 
the  supplements  would  absorb  moisture.  Owing  to  these  circum- 
stances, the  amounts  weighed  from  the  boxes  at  the  end  of  the  week 
were  occasionally  greater  than  the  amounts  weighed  in.  These  errors 
were  compensated  for  in  part  by  replacing  the  same  material  in  the 
feedboxes,  so  that  it  might  have  an  opportunity  to  return  to  air-dry 
condition  during  the  following  week.  Occasionally  a  cow  would  nose 
about  in  one  of  the  supplements  and  spill  a  small  quantity  on  the 
ground.  The  amounts  shown  by  the  records  as  being  consumed,  even 
though  very  small,  are  therefore  somewhat  larger  than  the  actual 
amounts. 

Quantities  of  Minerals  Consumed  Under  Free-Choice  Feeding 

The  records  obtained  during  parts  of  four  years  show  that  the 
animals  that  received  1  percent  of  common  salt  in  their  grain  mix- 
tures consumed  considerable  additional  amounts  when  given  access 
to  it.  The  amounts  eaten  by  growing  heifers  were  greater  than  those 
consumed  by  the  milk  cows,  as  shown  by  the  accompanying  table. 

The  amounts  of  ground  limestone  consumed  were  very  small, 
ranging  from  .01  to  .14  pound  per  animal  weekly  as  an  average  for  the 
different  periods.  There  was  little  difference  in  consumption  between 
the  heifer  group  and  the  cow  group,  and  the  amounts  did  not  change 
appreciably  after  the  bone  meal  feeding  was  begun.  The  average 
amount  consumed  per  animal  weekly  as  an  average  for  the  entire 
period  of  feeding  was  about  one-half  ounce  (.028  pound). 

The  introduction  of  bone  meal  into  the  group  of  supplements 
resulted  in  its  free  consumption  by  the  cow  group  for  a  few  weeks, 
when  the  amount  dropped  to  about  the  level  of  the  limestone  con- 
sumption. There  was  no  such  initial  variation  in  bone  meal  consump- 
tion with  the  heifer  group.  Upon  the  whole,  the  quantity  of  bone 
meal  eaten  was  quite  comparable  to  that  of  the  limestone,  the  average 
amount  for  the  entire  period  being  about  1%  ounces  (.077  pound) 
per  head  weekly,  the  amounts  in  both  cases  thus  being  almost  neg- 
ligible. 

Good  Rations  Seem  to  Satisfy  Calcium  and  Phosphorus  Needs 

It  is  evident  that  dairy  cattle  satisfy  their  desires  and  presum- 
ably their  needs  for  common  salt  as  they  have  opportunity.  Reason- 
ing along  this  line,  it  would  seem  that  if  dairy  cattle  suffer  from  defi- 
ciencies of  calcium  or  phosphorus,  or  both,  they  would  crave  these 
minerals  and  would  attempt  to  satisfy  their  desires  for  them.  The 
failure  of  the  animals  in  these  experiments  to  consume  more  than 
very  small  amounts  of  limestone  and  bone  meal  may  be  explained 
on  the  basis  of  one  of  two  assumptions:  either  that  dairy  cattle  re- 


W28} 


MINERAL  SUPPLEMENTS  FOU  DAIHV  CATTLE 


121 


TABLE  1. — AMOUNTS  OF  MINERALS  CONSUMED  BY  DAIRY  CATTLE  WHEN  MINERALS 
WERE  OFFERED  FREE-CHOICE  IN  EXERCISING  YARDS 


Heifer  group 

Cow  group 

Week  ending 

Number  of 
animals 

Limestone 

Salt 

Number  of 
animals 

Limestone 

Salt 

19S4  records 
Sept     8 

15 

/6s. 
5.0 

/6s. 
20.0 

39 

Ibs. 
3  0 

Iba. 
23  4 

15    

15 

1.4 

30.0 

39 

.6 

2.3  4 

11      22  

1.5 

.6 

38.5 

39 

.9 

15  0 

"      29  

15 

1.0 

32.7 

39 

-.1 

12  4 

Oct.    6  

15 

1.0 

13.9 

39 

.7 

11  3 

13 

15 

1.0 

13.9 

39 

.7 

9  3 

"      27l  

14 

-.3 

11.0 

40 

.1 

9  0 

Nov     3  

14 

1.3 

8.2 

40 

1.4 

5  0 

10  

14 

0 

12.8 

40 

.5 

5.5 

17 

14 

1.6 

10.0 

40 

-   S 

4 

"      24    

14 

.3 

4.0 

40 

1  0 

1  8 

Dec      1    

14 

1.2 

3.5 

40 

3  3 

N      

12 

-.2 

2.5 

40 

-1.0 

3  0 

15  

12 

.7 

4.6 

40 

-.2 

1.9 

Total 

212 

14.6 

205.6 

594 

7.3 

126  7 

Amount  per  animal 
weekly  

.069 

.970 

.012 

.213 

1925  records 
Mar.  16    

15 

3.0 

11.2 

40 

1   2 

23  

15 

0 

IS.  4 

40 

.6 

4.3 

"      30 

15 

.7 

13  5 

40 

-    1 

3  5 

Apr.    6  

15 

.6 

12.9 

40 

9 

2.2 

13 

15 

.9 

20.4 

40 

„     .? 

3  6 

"      20  

15 

-.1 

19.4 

40 

.2 

3.4 

"      27  

15 

.7 

24.0 

40 

.4 

3.0 

May    4  

15 

4.2 

12.5 

40 

.3 

3.5 

"      11  

15 

4.3 

37.9 

40 

.5 

4.7 

IS 

13 

19.6 

40 

.2 

2.1 

"      25  

11 

0 

10.7 

40 

.2 

3.3 

12 

2.3 

11.7 

40 

.2 

4.0 

8  

12 

.  \ 

9.5 

39 

0 

3.3 

"      15  

12 

.7 

20.3 

39 

.5 

7.9 

22 

12 

.6 

19.7 

39 

-.2 

15.2 

"      29  

12 

1.5 

22.3 

39 

-.1 

11.9 

July    6.  .  , 

12 

1.0 

27.7 

39 

.8 

17.7 

"      13  

20 

3.6 

22.1 

40 

2.0 

58.0 

20      . 

20 

.1 

27  9 

41 

25  4 

"      27  

21 

1.7 

IS.  7 

40 

1.3 

23.7 

Aug.    3  

21 

.2 

33.5 

40 

.7 

27.4 

"      10  

19 

-.6 

12.9 

40 

-.2 

23  .  s 

17 

19 

1   4 

2S   1 

40 

0 

44.0 

"      24  

19 

—  .4 

42  0 

40 

1.2 

39.9 

"      31  

19 

.2 

24.  1 

40 

1.7 

45.6 

Sept     7 

19 

2 

9  4 

40 

s 

35.5 

14    .... 

19 

0 

22  6 

40 

21.6 

"      21  

19 

—  .  1 

42.9 

40 

.8 

40.9 

"      28  

18 

1.4 

38.  9 

40 

6.2 

76.1 

'Two-week  period. 

ceiving  rations  containing  liberal  amounts  of  well-cured  legume  hay, 
which  is  high  in  lime  content,  and  a  grain  mixture  containing  pro- 
tein feeds  high  in  phosphorus  have  little  or  no  calcium  and  phosphor- 
us deficiency;  or  that  finely  ground  limestone  and  high-grade  bone 
meal  are  so  unpalatable  that  daily  cattle  refuse  to  eat  them  even 
tho  they  crave  them. 


122 


BULLETIN  No.  316 


[December, 


TABLE  1.— Continued 


Heifer  group 

Cow  group 

Week  ending 

Number  of 
animals 

Limestone 

Salt 

Number  of 
animals 

Limestone 

Salt 

1925  records 
Oct.    5  

18 

Ibs. 
.2 

Ibs. 
30  1 

40 

Ibs. 
8 

Ibs. 
37  3 

"      12  

18 

.3 

25.8 

42 

0 

41  3 

"19        .         .      . 

18 

0 

22  7 

42 

0 

28  7 

"      26  

18 

—2.0 

19  5 

42 

—  1  5 

25  2 

Nov.    2  

18 

2.4 

7.5 

42 

.5 

12  0 

9  

18 

0 

4.9 

42 

1.6 

11.8 

16  

18 

—  .4 

6  9 

42 

—  4 

12  4 

"      23  

18 

.6 

9.8 

42 

1  0 

20  5 

"      30 

17 

2 

10  4 

42 

1  2 

14  4 

Dec     7    ... 

17 

2 

10  0 

42 

3 

2  2 

14  

17 

—2.6 

17  0 

42 

4 

11  2 

"      21  

17 

—  1.2 

4.0 

42 

—  .6 

1.5 

Total 

676 

26  7 

803  4 

1658 

22  3 

775  2 

Amount  per  animal 

040 

1   189 

.014 

468 

1926  records 
Jan.    4  

17 

3.4 

18.3 

18    

17 

1   5 

21  7 

Feb.     1    

17 

.9 

14  2 

8  

17 

.2 

14.0 

15 

16 

1 

10  1 

"      22    

16 

—  2 

9.2 

Mar.    1.  . 

13 

1   1 

11.1 

8  

13 

1.0 

10.7 

"       15      . 

12 

7 

14  0 

22  

12 

.1 

21  2 

"      29  

12 

12.9 

Apr.    5  

12 

-.4 

6.0 

40 

—  .3 

—  !i 

"12      

12 

1 

11  4 

40 

-   2 

2.5 

19  

12 

.2 

9.1 

40 

2.0 

7.9 

"      26  

14 

.4 

8.5 

40 

.3 

6.6 

May    3 

14 

1  5 

6  2 

40 

4   1 

7.9 

10    

14 

.3 

15.4 

40 

1.1 

9.4 

17  

13 

S.2 

38 

1.7 

9.7 

"      24      . 

13 

2 

11  3 

38 

—2  0 

12.1 

"      31  

12 

—  .2 

15.4 

38 

—  .3 

12.9 

June    7  

12 

13.3 

38 

5.6 

21.7 

14 

12 

3 

9.2 

38 

1.5 

18.9 

"      21  

12 

0 

14.7 

40 

7.2 

32.8 

"      28 

12 

.3 

15  1 

40 

5  5 

28.7 

July    5    

12 

.9 

9.5 

40 

1.9 

30.6 

12  

12 

0 

40 

—  .1 

26.5 

19 

12 

.3 

7  8 

40 

6  9 

30.4 

"      26  

12 

0 

7.9 

40 

3.1 

30.2 

Of  these  assumptions  the  first  seems  the  more  logical,  since  it  has 
been  demonstrated  experimentally  that  cattle  suffering  severely  from 
phosphorus  deficiency  will  consume  bone  meal  when  it  is  offered  sep- 
arately, with  resultant  beneficial  effects.1  Other  investigators  and 
writers  state  that  cattle  will  eat  bone  meal  either  when  it  is  fed  alone 
or  when  mixed  with  salt.2  The  second  assumption,  therefore,  seems 

irTr.  Dept.  Agr.  (Union  S.  Africa)  1,  221-247,  1920.  Minn.  Agr.  Exp.  Sta. 
Bui.  229,  1926. 

2  Agr.  Gaz.  N.  S.  Wales  23,  885-888,  1912.  N.  S.  Wales  Dept.  Agr.  Sci.  Bui. 
12,  3-23,  1914.  Ohio  Agr.  Exp.  Sta.  Mo.  Bui.  5,  212-213,  1920.  Minn.  Agr.  Ext. 
Spec.  Bui.  94,  1924.  Mont.  Agr.  Exp.  Sta.  Circ.  122,  1924. 


1928} . 


MINERAL  SUPPLEMENTS  FOR  DAIRY  CATTLE 


123 


TABLE  1. — Continued 


Week 
ending 

Heifer  group 

Cow  group 

Number 
of 
animals 

Lime- 
stone 

Bone 
Meal 

Salt 

Number 
of 
animals 

Lime- 
stone 

Bone 

Meal 

Salt 

1926  records 
Aug     2    .  . 

12 
12 
12 
12 
12 

12 
12 
12 

7 

7 

7 

Ibs. 
.1 
.8' 

2.4 
.9 
.3 

.2 

2.5 
2.4 
-.2 

.2 
-.2 

23.1 
.047 

1.5 
2  .  5 
1.0 
.  5 

2.3 
5.2 
1.0 
.3 
14.3 

.170 

/6s. 

i.'s1 

2.4 
1.3 
.4 

.1 
.4 
.3 
0 

1.5 
0 

8.'2 
.078 

—  .5 
.7 
.3 
2.0 

4.5 
1.0 
2.0 
0 
10.0 

.119 

/6s. 
10.0 
8.8 
16.2 
18.3 
23.9 

1.4 
13.2 
6.5 
-.2 

2.3 
-.3 

43216 
.880 

—  .5 
7.1 
5.1 
8.8 

2.0 
3.5 
9.5 

2.5 
38.0 

.454 

40 
40 
40 
40 
40 

40 
40 
40 
39 

39 
39 
39 
39 

39 
39 
39 
39 
38 

38 
39 
1456 

38 
38 
38 
38 

38 
38 
40 
23 
291 

Ibs. 
.1 
2.01 
.3 
4.6 
3.5 

.7 
3.7 
-1.3 

2.9 

1.6 
-.8 
-.3 
-.3 

-.2 
.6 
-.3 
-1.7 
2.4 

1.2 
1.1 

57  .  S 

.041 

-2.0 
1.0 
.  5 
1.0 

.3 

-3.8 
3.0 
-1.2 
-1.2 

0 

Ibs. 

16.5' 

12.  S 
19.2 
2S.O 

23.7 
10.0 
1.7 
6.6 

2.8 
4.7 
7.8 
4.7 

9.4 

1.5 
.1 

-.8 
.6 

-.3 
.1 
149.1 

.200 

-.4 
1.1 
1.0 
3.0 

2.5 
-6.4 
10.5 
-1.5 

9.8 

.034 

/6s. 
34.7 
38.5 
34  .  8 
50.6 
39.4 

17.8 
16.7 

11.7 
20.8 

4.3 
8.2 
15.1 
11.3 

5.5 
4.4 
-.4 
0 
-2.9 

0 

.4 
599.6 

.412 

1.7 
5.3 
4.2 
7.0 

10.3 
11.9 
10.6 

5.0 
56.0 

.192 

9    .... 

16  

23      . 

30    .... 

Sept      6    .... 

13  

"      20      . 

27    .. 

Oct     4  

11  

"       18  
25  

Nov.    1  
8  
"      15  
"      22  

"      29  

Dec.    6  
"       13  
Total  

491 

11 

11 
11 
11 

11 
11 
9 
9 
84 

Amount  per 
animal  weekly 

1027  records 
Apr.    4.  . 
11.  . 
"       18.  . 
"       25.  . 

May    2.  . 
9.  . 
"      16.  . 
"      23.  . 
Total. 

Amount  per 
animal  weekly 

JBeginning  with  this  week  and  continuing  to  the  end  of  the  experiment,  the  limestone  and  bone 
meal  were  mixed  with  common  salt  at  the  rate  of  4  parts  of  limestone  or  bone  meal  to  1  part  of  salt. 
The  data  showing  the  amounts  of  limestone  and  bone  meal  consumed  subsequent  to  August  2,  1926, 
are  therefore  given  in  terms  of  the  mixtures. 

hardly  tenable.  Furthermore,  the  animals  in  this  experiment  readily 
consumed  grain  mixtures  containing  bone  meal  during  the  period  when 
the  mineral  supplements  were  not  fed  free-choice,  and  in  other  experi- 
ments at  this  Station,  dairy  cows  were  fed  successfully  on  grain  mix- 
tures containing  3  percent  of  ground  limestone.  The  fact  that  a  feed 
is  eaten  readily  when  offered  in  a  mixture  is  not,  however,  conclusive 
evidence  that  it  will  be  eaten  if  offered  separately;  in  earlier  experi- 
ments at  this  Station  in  the  self -feeding  of  dairy  cows  feeds  offered 
separately  were  neglected  even  tho  eaten  without  trouble  when  offered 
in  combination.1 

From  the  results  of  the  present  experiment  and  previous  invoti- 
gations  it  seems  doubtful  whether  dairy  cows  of  moderate  to  good 
productivity  suffer  from  calcium  or  phosphorus  deficiency  when  re- 


'111.  Agr.  Exp.  Sta.  Bui.  289.    1927. 


124 


BULLETIN  No.  316 


TABLE  1. — Concluded 


Week 
ending 

Group  I1 

Group  21 

Number 
of 
animals 

Lime- 
stone 

Bone 
Meal 

Salt 

Number 
of 
animals 

Lime- 
stone 

Bone 
Meal 

Salt 

May  30.  ... 

23 

21 
23 
23 
20 

20 
20 
20 
20 

20 
20 
20 
20 
20 

20 
20 
20 
20 

20 
20 
20 
20 
21 

21 
21 
21 
0 

534 

Ibs. 
.7 

1.0 
1.0 
0 

.7 

.8 
0 
0 
-1.0 

1.2 
3.1 
5.5 
2.0 
1.2 

1.6 
-6.1 
.6 
.8 

-6.0 
3.6 
2.0 
-.2 

.8 

0 

-.4 
.6 

Ibs. 
1.0 

.6 
.4 
.2 

1.8 

0 

.7 
0 
-.2 

1.7 
.1 
3.3 

2.2 

.5 

8.6 
1.8 
-7.6 
10.3 

-12.8 
4.3 
2.0 
0 
.5 

2.0 
-.7 
.2 

Ibs. 
5.2 

9.5 
12.1 
4.0 
4.4 

1.9 
3.7 
3.0 

8.2 

8.4 
10.9 
15.3 

8.5 
8.9 

6.0 
6.9 
2.8 
-3.2 

1.0 
5.3 
12.0 
11.0 
9.0 

6.5 
1.0 
4.2 

18 

18 
18 
18 
21 

21 
21 
21 
21 

21 
21 
21 
21 
21 

21 
21 
21 
21 

21 
21 
21 
23 
21 

21 
21 
21 
43 

579 

Ibs. 
.2 

0 
1.0 
.2 
1.7 

.1 
.5 
0 
-1.2 

.7 
.7 
.8 
1.5 
1.1 

0 
2.0 

-7.7 
4.2 

-2.9 
8.7 
3.5 
2.0 
2 

.3 
-.5 
.3 
3.7 
21.1 

.036 

Ibs. 
0 

0 
1.0 
0 
.2 

.4 
.4' 
1.0 
-1.0 

.5 
1.0 
.6 
1.5 
0 

2.6 
4.9 
-4.3 
11.2 

-10.8 
4.8 
3.9 
0 
2.3 

1.0 
3.8 
.6 
1.4 
27.0 

.047 

Ibs. 
3.0 

3.1 

6.8 
6.2 
10.6 

8.9 
.7 
11.4 
13.8 

19.0 

17.2 
24.9 
16.9 
12.9 

8.8 
9.7 
9.9 
7.5 

18.2 
20.2 
19.1 
17.4 
18.4 

15.7 
12.9 
13.0 
19.8 
346.0 

.598 

"       13  

20    . 

27  

July    4  

11  

18      . 

"      25  

Aug.     1  

8 

15.  .  . 

"      22  

"      29  

Sept.    5.  .  . 

12  

"      19  

26 

Oct.    3.  .  . 

"       10  
17 

24.  .  . 

"      31  

Nov.    7.  .  . 

14    .. 

"      21  
"      28  
Total.  . 

13.5 
.025 

20.9 
.039 

166.5 
.312 

Amount  per 
animal  weekly. 

'Beginning  May  24  the  animals  were  divided  into  two  approximately  equal  groups.  Each  group 
contained  cows  and  heifers  and  was  kept  in  a  separate  yard. 

Amounts  (exclusive  of  salt  admixture)  per  animal  (all  groups)  weekly  for  four  years  were:  lime- 
stone, .028  pound;  bone  meal,  .077  pound;  salt  offered  alone,  .54  pound. 


ceiving  rations  containing  liberal  amounts  of  well-cured  legume  hay, 
which  is  high  in  lime  content,  and  a  well-balanced  grain  mixture  con- 
taining protein  supplements  high  in  phosphorus. 


Summary 

No  particular  fraying  or  desire  for  mineral  supplements  other  than  for 
common  salt  was  demonstrated  in  the  dairy  cattle  kept  under  the  conditions  of 
this  experiment.  The  cattle  were  kept  in  barns  and  dry  lots,  under  ordinary 
herd  conditions,  and  were  fed  rations  consisting  of  well-cured  legume  hay,  corn 
silage,  and  a  grain  mixture  containing  protein  feeds  rich  in  phosphorus.  In  addi- 
tion common  salt,  finely  ground  limestone,  and  bone  meal  of  feeding  grade  were 
supplied  free-choice.  Almost  insignificant  amounts  of  the  limestone  and  bone 
meal  were  consumed  when  offered  in  this  manner. 

Feeding  common  salt  at  the  rate  of  1  percent  of  the  grain  mixture  is  insuffi- 
cient to  satisfy  the  desires  of  dairy  cattle  for  this  compound.  It  was  found  that 
when  additional  salt  was  supplied  in  feed  boxes  in  the  exercising  yards,  quite 
large  amounts  were  consumed. 


"v.     .  *->' 

•9 


m& 


- 


UNIVERSITY  OF  ILLINOIS-URBANA 


